1 /* 2 * reserved comment block 3 * DO NOT REMOVE OR ALTER! 4 */ 5 /* 6 * Licensed to the Apache Software Foundation (ASF) under one or more 7 * contributor license agreements. See the NOTICE file distributed with 8 * this work for additional information regarding copyright ownership. 9 * The ASF licenses this file to You under the Apache License, Version 2.0 10 * (the "License"); you may not use this file except in compliance with 11 * the License. You may obtain a copy of the License at 12 * 13 * http://www.apache.org/licenses/LICENSE-2.0 14 * 15 * Unless required by applicable law or agreed to in writing, software 16 * distributed under the License is distributed on an "AS IS" BASIS, 17 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 18 * See the License for the specific language governing permissions and 19 * limitations under the License. 20 */ 21 22 package com.sun.org.apache.xpath.internal.axes; 23 24 import com.sun.org.apache.xml.internal.dtm.Axis; 25 import com.sun.org.apache.xml.internal.dtm.DTM; 26 import com.sun.org.apache.xml.internal.dtm.DTMAxisTraverser; 27 import com.sun.org.apache.xml.internal.dtm.DTMFilter; 28 import com.sun.org.apache.xml.internal.dtm.DTMIterator; 29 import com.sun.org.apache.xpath.internal.Expression; 30 import com.sun.org.apache.xpath.internal.XPathContext; 31 import com.sun.org.apache.xpath.internal.compiler.Compiler; 32 import com.sun.org.apache.xpath.internal.compiler.OpCodes; 33 import com.sun.org.apache.xpath.internal.compiler.OpMap; 34 import com.sun.org.apache.xpath.internal.patterns.NodeTest; 35 import org.w3c.dom.DOMException; 36 37 /** 38 * This class implements an optimized iterator for 39 * descendant, descendant-or-self, or "//foo" patterns. 40 * @see com.sun.org.apache.xpath.internal.axes.LocPathIterator 41 * @xsl.usage advanced 42 */ 43 public class DescendantIterator extends LocPathIterator 44 { 45 static final long serialVersionUID = -1190338607743976938L; 46 /** 47 * Create a DescendantIterator object. 48 * 49 * @param compiler A reference to the Compiler that contains the op map. 50 * @param opPos The position within the op map, which contains the 51 * location path expression for this itterator. 52 * 53 * @throws javax.xml.transform.TransformerException 54 */ DescendantIterator(Compiler compiler, int opPos, int analysis)55 DescendantIterator(Compiler compiler, int opPos, int analysis) 56 throws javax.xml.transform.TransformerException 57 { 58 59 super(compiler, opPos, analysis, false); 60 61 int firstStepPos = OpMap.getFirstChildPos(opPos); 62 int stepType = compiler.getOp(firstStepPos); 63 64 boolean orSelf = (OpCodes.FROM_DESCENDANTS_OR_SELF == stepType); 65 boolean fromRoot = false; 66 if (OpCodes.FROM_SELF == stepType) 67 { 68 orSelf = true; 69 // firstStepPos += 8; 70 } 71 else if(OpCodes.FROM_ROOT == stepType) 72 { 73 fromRoot = true; 74 // Ugly code... will go away when AST work is done. 75 int nextStepPos = compiler.getNextStepPos(firstStepPos); 76 if(compiler.getOp(nextStepPos) == OpCodes.FROM_DESCENDANTS_OR_SELF) 77 orSelf = true; 78 // firstStepPos += 8; 79 } 80 81 // Find the position of the last step. 82 int nextStepPos = firstStepPos; 83 while(true) 84 { 85 nextStepPos = compiler.getNextStepPos(nextStepPos); 86 if(nextStepPos > 0) 87 { 88 int stepOp = compiler.getOp(nextStepPos); 89 if(OpCodes.ENDOP != stepOp) 90 firstStepPos = nextStepPos; 91 else 92 break; 93 } 94 else 95 break; 96 97 } 98 99 // Fix for http://nagoya.apache.org/bugzilla/show_bug.cgi?id=1336 100 if((analysis & WalkerFactory.BIT_CHILD) != 0) 101 orSelf = false; 102 103 if(fromRoot) 104 { 105 if(orSelf) 106 m_axis = Axis.DESCENDANTSORSELFFROMROOT; 107 else 108 m_axis = Axis.DESCENDANTSFROMROOT; 109 } 110 else if(orSelf) 111 m_axis = Axis.DESCENDANTORSELF; 112 else 113 m_axis = Axis.DESCENDANT; 114 115 int whatToShow = compiler.getWhatToShow(firstStepPos); 116 117 if ((0 == (whatToShow 118 & (DTMFilter.SHOW_ATTRIBUTE | DTMFilter.SHOW_ELEMENT 119 | DTMFilter.SHOW_PROCESSING_INSTRUCTION))) || 120 (whatToShow == DTMFilter.SHOW_ALL)) 121 initNodeTest(whatToShow); 122 else 123 { 124 initNodeTest(whatToShow, compiler.getStepNS(firstStepPos), 125 compiler.getStepLocalName(firstStepPos)); 126 } 127 initPredicateInfo(compiler, firstStepPos); 128 } 129 130 /** 131 * Create a DescendantIterator object. 132 * 133 */ DescendantIterator()134 public DescendantIterator() 135 { 136 super(null); 137 m_axis = Axis.DESCENDANTSORSELFFROMROOT; 138 int whatToShow = DTMFilter.SHOW_ALL; 139 initNodeTest(whatToShow); 140 } 141 142 143 /** 144 * Get a cloned Iterator that is reset to the beginning 145 * of the query. 146 * 147 * @return A cloned NodeIterator set of the start of the query. 148 * 149 * @throws CloneNotSupportedException 150 */ cloneWithReset()151 public DTMIterator cloneWithReset() throws CloneNotSupportedException 152 { 153 154 DescendantIterator clone = (DescendantIterator) super.cloneWithReset(); 155 clone.m_traverser = m_traverser; 156 157 clone.resetProximityPositions(); 158 159 return clone; 160 } 161 162 /** 163 * Returns the next node in the set and advances the position of the 164 * iterator in the set. After a NodeIterator is created, the first call 165 * to nextNode() returns the first node in the set. 166 * 167 * @return The next <code>Node</code> in the set being iterated over, or 168 * <code>null</code> if there are no more members in that set. 169 * 170 * @throws DOMException 171 * INVALID_STATE_ERR: Raised if this method is called after the 172 * <code>detach</code> method was invoked. 173 */ nextNode()174 public int nextNode() 175 { 176 if(m_foundLast) 177 return DTM.NULL; 178 179 if(DTM.NULL == m_lastFetched) 180 { 181 resetProximityPositions(); 182 } 183 184 int next; 185 186 com.sun.org.apache.xpath.internal.VariableStack vars; 187 int savedStart; 188 if (-1 != m_stackFrame) 189 { 190 vars = m_execContext.getVarStack(); 191 192 // These three statements need to be combined into one operation. 193 savedStart = vars.getStackFrame(); 194 195 vars.setStackFrame(m_stackFrame); 196 } 197 else 198 { 199 // Yuck. Just to shut up the compiler! 200 vars = null; 201 savedStart = 0; 202 } 203 204 try 205 { 206 do 207 { 208 if(0 == m_extendedTypeID) 209 { 210 next = m_lastFetched = (DTM.NULL == m_lastFetched) 211 ? m_traverser.first(m_context) 212 : m_traverser.next(m_context, m_lastFetched); 213 } 214 else 215 { 216 next = m_lastFetched = (DTM.NULL == m_lastFetched) 217 ? m_traverser.first(m_context, m_extendedTypeID) 218 : m_traverser.next(m_context, m_lastFetched, 219 m_extendedTypeID); 220 } 221 222 if (DTM.NULL != next) 223 { 224 if(DTMIterator.FILTER_ACCEPT == acceptNode(next)) 225 break; 226 else 227 continue; 228 } 229 else 230 break; 231 } 232 while (next != DTM.NULL); 233 234 if (DTM.NULL != next) 235 { 236 m_pos++; 237 return next; 238 } 239 else 240 { 241 m_foundLast = true; 242 243 return DTM.NULL; 244 } 245 } 246 finally 247 { 248 if (-1 != m_stackFrame) 249 { 250 // These two statements need to be combined into one operation. 251 vars.setStackFrame(savedStart); 252 } 253 } 254 } 255 256 /** 257 * Initialize the context values for this expression 258 * after it is cloned. 259 * 260 * @param context The XPath runtime context for this 261 * transformation. 262 */ setRoot(int context, Object environment)263 public void setRoot(int context, Object environment) 264 { 265 super.setRoot(context, environment); 266 m_traverser = m_cdtm.getAxisTraverser(m_axis); 267 268 String localName = getLocalName(); 269 String namespace = getNamespace(); 270 int what = m_whatToShow; 271 // System.out.println("what: "); 272 // NodeTest.debugWhatToShow(what); 273 if(DTMFilter.SHOW_ALL == what 274 || NodeTest.WILD.equals(localName) 275 || NodeTest.WILD.equals(namespace)) 276 { 277 m_extendedTypeID = 0; 278 } 279 else 280 { 281 int type = getNodeTypeTest(what); 282 m_extendedTypeID = m_cdtm.getExpandedTypeID(namespace, localName, type); 283 } 284 285 } 286 287 /** 288 * Return the first node out of the nodeset, if this expression is 289 * a nodeset expression. This is the default implementation for 290 * nodesets. 291 * <p>WARNING: Do not mutate this class from this function!</p> 292 * @param xctxt The XPath runtime context. 293 * @return the first node out of the nodeset, or DTM.NULL. 294 */ asNode(XPathContext xctxt)295 public int asNode(XPathContext xctxt) 296 throws javax.xml.transform.TransformerException 297 { 298 if(getPredicateCount() > 0) 299 return super.asNode(xctxt); 300 301 int current = xctxt.getCurrentNode(); 302 303 DTM dtm = xctxt.getDTM(current); 304 DTMAxisTraverser traverser = dtm.getAxisTraverser(m_axis); 305 306 String localName = getLocalName(); 307 String namespace = getNamespace(); 308 int what = m_whatToShow; 309 310 // System.out.print(" (DescendantIterator) "); 311 312 // System.out.println("what: "); 313 // NodeTest.debugWhatToShow(what); 314 if(DTMFilter.SHOW_ALL == what 315 || localName == NodeTest.WILD 316 || namespace == NodeTest.WILD) 317 { 318 return traverser.first(current); 319 } 320 else 321 { 322 int type = getNodeTypeTest(what); 323 int extendedType = dtm.getExpandedTypeID(namespace, localName, type); 324 return traverser.first(current, extendedType); 325 } 326 } 327 328 /** 329 * Detaches the iterator from the set which it iterated over, releasing 330 * any computational resources and placing the iterator in the INVALID 331 * state. After<code>detach</code> has been invoked, calls to 332 * <code>nextNode</code> or<code>previousNode</code> will raise the 333 * exception INVALID_STATE_ERR. 334 */ detach()335 public void detach() 336 { 337 if (m_allowDetach) { 338 m_traverser = null; 339 m_extendedTypeID = 0; 340 341 // Always call the superclass detach last! 342 super.detach(); 343 } 344 } 345 346 /** 347 * Returns the axis being iterated, if it is known. 348 * 349 * @return Axis.CHILD, etc., or -1 if the axis is not known or is of multiple 350 * types. 351 */ getAxis()352 public int getAxis() 353 { 354 return m_axis; 355 } 356 357 358 /** The traverser to use to navigate over the descendants. */ 359 transient protected DTMAxisTraverser m_traverser; 360 361 /** The axis that we are traversing. */ 362 protected int m_axis; 363 364 /** The extended type ID, not set until setRoot. */ 365 protected int m_extendedTypeID; 366 367 /** 368 * @see Expression#deepEquals(Expression) 369 */ deepEquals(Expression expr)370 public boolean deepEquals(Expression expr) 371 { 372 if(!super.deepEquals(expr)) 373 return false; 374 375 if(m_axis != ((DescendantIterator)expr).m_axis) 376 return false; 377 378 return true; 379 } 380 381 382 } 383